Brawn: Ferrari running out of time

Asked if the next two races in North America are particularly crucial for Ferrari, Brawn replied: "Yes. I'd hate to go to Magny-Cours (for the French Grand Prix) in a worse condition than we are now.

"We're running out of races, and we need to try and reverse the trend if we've got any chance of winning the championships. So these are two very important races."

Ferrari had a lacklustre start to the Canadian Grand Prix weekend, with both cars well outside the top ten in today's final practice session.

Brawn said their lack of competitiveness in Montreal was down to the cool weather conditions and the new track - but he remained optimistic that conditions will improve on Saturday.

The Briton explained: "The tyre has a working rate, temperature wise, and we're a bit outside that at the moment, because it was cooler today than we expected, and we're not generating the heat we need. So the grip is not there, as the track's so green.

"It's very slippery and the tyres are graining, and when it happens you're out of place from where you want to be.

"It's a big loss, and we tried two different compounds, and we had a similar result. I'm optimistic that tomorrow, with more rubber and the temperature building up, we'll be back to where we want to be.

"We know these tyres work well once we get away from the graining issue that we had today. So I'm reasonably optimistic."

Brawn admitted, however, that Ferrari's chances rely on Felipe Massa also taking points away from Renault - as Fernando Alonso can mathematically defend his title by just finishing second in every race until the end of the season.

"We need to swing the difference (to Alonso and Renault) the other way," Brawn said. "Fernando can score second places from now on, so to make up the points deficit, we need to have Felipe up there, and hope that Alonso will not finish a few races.

"Felipe is very good, I've got no concerns (that he can do the job). If we can give him the car and the tyres, he'll be competitive; he's shown that.

"But it will be a very difficult challenge - I'm not disguising that, but we have to try.